Method and Apparatus For Condensing Water From Ambient Air

ABSTRACT

There is provided methods and apparatus ( 2 ) for collecting water from ambient air. The apparatus has at least one condensation surface which is cooled to, or below, the dew point of the ambient air. The cooling of the condensation surface is effected by utilising a gas to reduce the partial pressure of refrigerant vapour to effect evaporation of liquid refrigerant. Water in ambient air that contacts the cooled condensation surface condenses and is collected. There is also provided apparatus for effecting cooling and/or heating.

FIELD OF THE INVENTION

The present invention broadly relates to a method and apparatus forcondensing water for collection from ambient air. The apparatus in atleast one form provides a means for generating potable water forconsumption or other purposes and finds particular application in areaswhere potable water supplies are limited.

BACKGROUND OF THE INVENTION

In many locations around the world access to a fresh potable watersupply is limited, forcing many to use water for everyday needs thatwould not generally be deemed suitable for such use. Indeed, many watersupplies are contaminated or polluted and in order to be able to use thewater safely, it is necessary for the water to be boiled or treated insome other way.

While yachts and ships carry their own water supplies during a voyage,it is often necessary to restrict daily usage of the available water dueto access to fresh water supplies other than rainfall being unavailable.Similarly, mining companies, road and rail repair gangs as well as forinstance military units operating in remote locations, and islandresorts all have a need for fresh water.

Water, of course, has thousands of uses in addition to being required tosustain life. Such uses include washing and use in industrial processesamongst others. In areas or locations where the supply of water islimited, it is desirable to have access to regular supplies of freshwater. While supplies can be replenished by rainwater, rainfall can bevariable and insufficient. Moreover, the cost of transporting freshwater to remote locations on a regular basis can be expensive.

Apparatus for condensing water from ambient air are disclosed inEuropean patent No. 0597716 and U.S. Pat. No. 5,857,344. Both of theseapparatus comprise a refrigeration system incorporating an electriccompressor, for achieving cooling of ambient air by compression andsubsequent expansion of a refrigerant to effect condensation of waterfrom the air that is then collected.

U.S. Pat. No. 6,156,102 discloses an apparatus and method for collectingwater from ambient air involving passing the air into contact with ahygroscopic solution. The hygroscopic solution absorbs the moisture fromthe air. The moisture is subsequently evaporated from the hygroscopicsolution and collected. Evaporation of the moisture is achieved byheating the hygroscopic liquid or by evaporating the moisture undervacuum. A similar arrangement involving directing ambient air intocontact with a sorbent material for absorption of moisture from the airprior to subsequent separation and collection of the absorbed moistureis described in U.S. Pat. No. 6,336,957.

SUMMARY OF THE INVENTION

In an aspect of the present invention there is provided a method forcollecting water from ambient air, the method comprising:

providing at least one condensation surface for contact with the ambientair;

passing a gas into an enclosed space containing a gaseous mixture of thegas and refrigerant vapour evaporated from a liquid refrigerant suchthat further refrigerant vapour evaporates into the enclosed space fromthe liquid refrigerant, and heat is thereby drawn into the refrigerantfrom the condensation surface cooling the condensation surface to, orbelow, the dew point of the water in the ambient air;

passing the gaseous mixture from the enclosed space;

contacting the cooled condensation surface with the ambient air toeffect condensation of water from the ambient air onto the condensationsurface; and

collecting the condensed water.

Typically, the method will further comprise condensing the refrigerantvapour in the gaseous mixture passed from the enclosed space back intoliquid refrigerant to separate the refrigerant vapour from the gas,returning the gas from the gaseous mixture to the enclosed space forgenerating more of the gaseous mixture, and recirculating the liquidrefrigerant condensed from the gaseous mixture.

Preferably, the gaseous mixture will be passed from the enclosed spaceinto contact with a liquid absorbent that absorbs the gas from thegaseous mixture thereby forming a solution, and the gas will beseparated from the solution for the return of the gas to the enclosedspace and recycling of the liquid absorbent for contact with more of thegaseous mixture.

Preferably, the liquid refrigerant condensed from the gaseous mixture isrecirculated concurrently with the passage of the gas into the enclosedspace and passage of the gaseous mixture from the enclosed space intocontact with the liquid absorbent, such that the condensation surface iscooled in a continuous cycle.

Preferably, the liquid refrigerant will be agitated as the gas is passedinto the enclosed space. Most preferably, the agitation of the liquidrefrigerant will be achieved by bubbling the gas through the liquidrefrigerant into the enclosed space.

Preferably, the method will further comprise monitoring temperature ofambient air flowing from the condensation surface, and adjusting theflow rate at which the ambient air flows into contact with thecondensation surface to a desired flow rate to promote the condensationof the water from the ambient air onto the condensation surface.

The ambient air is cooled by contact with the condensation surface andthe cooled ambient air may be used for cooling the refrigerant vapour inthe gaseous mixture passed from the enclosed space, to facilitatecondensing the refrigerant vapour back into the liquid refrigerant.Preferably, the gaseous mixture will be passed from the enclosed spaceinto a condenser in which the refrigerant vapour is condensed.

Accordingly, the method may also comprise adjusting the flow rate of theambient air flowing from the condensation surface to the condenser topromote the condensation of the refrigerant vapour. Evaluating whetherthe flow rate of the ambient air flowing from the condensation surfaceneeds to be adjusted to promote the condensing of the refrigerant vapourmay comprise:

measuring pressure within the condenser;

measuring temperature within the condenser; and

assessing the measured pressure and the measured temperature.

In another aspect of the present invention there is provided anapparatus for collecting water from ambient air, the apparatuscomprising:

at least one condensation surface for contact with the ambient air;

an evaporator for receiving liquid refrigerant and defining an enclosedspace for a gaseous mixture of refrigerant vapour evaporated from theliquid refrigerant and a gas;

an inlet opening into the evaporator for passage of the gas into thespace to cause further evaporation of the liquid refrigerant into thespace such that heat is drawn into the liquid refrigerant from thecondensation surface, and the condensation surface is thereby cooled to,or below, the dew point of the water in the ambient air to effectcondensation of water from the ambient air onto the condensation surfacefor collection of the water; and

an outlet for passage of the gaseous mixture from the space.

Preferably, the apparatus will further comprise a separation system forseparating the gas in the gaseous mixture from the refrigerant andcondensing the refrigerant vapour back into liquid refrigerant, for thereturn of the gas to the enclosed space in the evaporator and recyclingof the liquid refrigerant.

Preferably, the separation system will comprise a condenser forreceiving the gaseous mixture from the evaporator and condensing therefrigerant vapour in the gaseous mixture back into the liquidrefrigerant, the condenser being adapted to receive liquid absorbent andfacilitate contact of the gaseous mixture with the liquid absorbent foradsorption of the gas into the liquid absorbent to form a solution andthereby separate the gas from the refrigerant vapour.

Preferably, in use, the condenser will house a bath comprising a layerof the liquid refrigerant and a layer of the solution; and the condenserwill be adapted for receiving the gaseous mixture for contact of thegaseous mixture with the liquid absorbent to form the solution, prior topassage of the solution into the bath. Generally, the liquid refrigerantwill have a lower density than the solution, and the solution willseparate from the layer of liquid refrigerant into the layer of thesolution.

Preferably, the condenser will further comprise a mixer unit arrangedwithin the condenser for receiving the liquid absorbent, wherein themixer unit is adapted for creating a flow of the liquid absorbent over asurface of the mixer unit for facilitating the contact of the gas withthe liquid absorbent. Generally, the mixer unit will incorporate an openwell for receiving the liquid absorbent and providing the flow of theliquid absorbent down the surface of the mixer unit with overflow of theliquid absorbent from the well.

Preferably, the mixer unit will be adapted for promoting turbulence inthe liquid absorbent as the liquid absorbent flows down the surface ofthe mixer unit to enhance absorption of the gas by the liquid absorbent.Typically, the mixer unit will have at least one ridge defined in thesurface of the mixer unit and which lies across the surface forpromoting the turbulence in the liquid absorbent. Preferably, the mixerunit will have a plurality of ridges, the ridges being spaced apart fromone another down the mixer unit and extending substantially entirelyaround the outer periphery of the mixer unit.

Preferably, the mixer unit will be mounted on gimbals arranged withinthe condenser for maintaining the mixer unit in a substantially uprightposition.

Preferably, the separation system will further comprise a separationreservoir for evaporation of the gas from the liquid absorbent, theseparation reservoir comprising:

a housing;

an inlet for passage of the liquid absorbent into the housing, the gasevaporating from the liquid absorbent within the housing; and

an outlet for return of the gas evaporated from the liquid absorbent tothe evaporator.

The separation reservoir will typically be adapted for being heated tofacilitate evaporation of the gas from liquid absorbent.

Preferably, the separation system will further comprise a pump systemfor elevating the liquid absorbent to an elevated position for flow ofthe liquid absorbent to the condenser for contact with further of thegaseous mixture from the evaporator, the pump system comprising:

a heating reservoir for receiving the liquid absorbent and being heatedfor causing the liquid absorbent to be forced from the heatingreservoir;

a riser tube for receiving the liquid absorbent from the heatingreservoir upon the heating reservoir being heated; and

a collection reservoir arranged at the elevated position and into whichthe tube opens for collection of the liquid absorbent, the collectionreservoir being adapted for passage of the liquid absorbent from thecollection reservoir to the condenser.

Preferably, the collection reservoir will have a first outlet forpassage of the liquid absorbent from the collection reservoir to thecondenser, an interior space for receiving the gas together withabsorbent vapour which evaporate from the liquid absorbent with travelalong the riser tube, and a further outlet for passage of the gasseparated from the liquid absorbent from the collection reservoir to theevaporator.

Preferably, the first outlet of the collection reservoir will open intoa conduit for directing the liquid absorbent to the condenser, whereinthe conduit passes through the separation reservoir for heat exchangewith the solution from the condenser.

Preferably, the further outlet of the collection reservoir will openinto a passageway connecting the first outlet of the separationreservoir with the evaporator. The passageway will desirably have aninclined region for trapping liquid absorbent that condenses in thepassageway from the absorbent vapour, and draining the condensed liquidabsorbent into the separation reservoir.

Preferably, the apparatus will also comprise a heat exchanger for heatexchange between the gaseous mixture and the gas with passage of thegaseous mixture from the space in the evaporator to the condenser andpassage of the gas from the separation system to the evaporator.Generally, the heat exchanger will usually also be adapted for receivingthe condensed refrigerant for heat exchange with the gaseous mixture andthe gas, with passage of the condensed refrigerant from the condenser tothe evaporator.

Moreover, the apparatus will preferably comprise a casing housing thecondenser and the evaporator, for directing the ambient air from theevaporator into contact with the condenser. Preferably, a fan will beprovided for producing flow of the ambient air through the casing fromexterior of the casing. More preferably, the condensation surface willusually be arranged at an angle relative to horizontal for facilitatingthe collection of the condensed water. The angle will typically be in arange from about 30° C. to about 60° C. and preferably, from about 40°C. to about 50° C.

Preferably, the apparatus will also comprise a control system forcontrolling flow rate of the ambient air into contact with thecondensation surface, the control system comprising:

a temperature sensor for determining temperature of the ambient airflowing from the condensation surface;

wherein the control system is adapted to monitor the temperaturedetermined by the temperature sensor and adjust the flow rate of theambient air flowing into contact with the condensation surface topromote condensation of the water from the ambient air onto thecondensation surface.

Preferably also, the apparatus will be adapted to direct the ambient airflowing from the condensation surface to the condenser, and wherein thecontrol system will further comprise an adjustable air intake operableto adjust flow rate of the ambient air flowing from the evaporator tothe condenser relative to the flow rate of the ambient air flowing intocontact with the condensation surface, to thereby alter temperature andpressure within the condenser to promote the condensation of therefrigerant vapour.

Most preferably, the control system will comprise a further temperaturesensor for measuring temperature in the condenser, and a pressure sensorfor measuring pressure within the condenser, and the control system willbe further adapted to assess the temperature measured by the furthertemperature sensor and the pressure measured by the pressure sensor, andoperate the adjustable air intake to alter the flow rate of the ambientair flowing to the condenser.

Preferably, the inlet opening into the evaporator will be located forbubbling the gas through the liquid refrigerant into the enclosed spaceof the evaporator. Bubbling the gas through the liquid refrigerantagitates the liquid refrigerant increasing heat transfer from theambient air to the liquid refrigerant.

In yet another aspect of the present invention there is provided anevaporator for effecting condensation of water from ambient air, theevaporator comprising:

at least one condensation surface for contact with the ambient air;

a housing for receiving liquid refrigerant and having an interiorenclosed space for a gaseous mixture of refrigerant vapour evaporatedfrom the liquid refrigerant and a gas;

an inlet for passage of the gas into the space to cause furtherevaporation of the liquid refrigerant into the enclosed space such thatheat is drawn into the liquid refrigerant from the condensation surfaceand the condensation surface is thereby cooled to, or below, the dewpoint of the water in the ambient air to effect condensation of thewater from the ambient air onto the condensation surface for collectionof the water; and

an outlet for passage of the gaseous mixture from the enclosed space.

Preferably, the, or each, condensation surface will be a surface of acooling fin respectively, and the housing of the evaporator willcomprise:

an upper region for receiving the gaseous mixture of the gas and therefrigerant vapour;

a lower region for being at least partly filled with the liquidrefrigerant and being spaced from the upper region; and

at least one conduit that opens at one end into the upper region of thehousing and at an opposite end into the lower region; and

wherein the, or each, cooling fin is arranged between the upper regionand the lower region for contact with the ambient air.

Typically, a plurality of cooling fins will be spaced apart from eachother and arranged one next to another for contact with the ambient air.

In yet another aspect there is provided a method for separating a gasfrom a refrigerant vapour in a gaseous mixture, the method comprising:

providing a condenser adapted for condensing the refrigerant vapour intoliquid refrigerant, the condenser housing a mixer unit for receiving aliquid absorbent for absorbing the gas and which is adapted forfacilitating contact of the liquid absorbent with the gaseous mixture;

passing the gaseous mixture into the condenser to effect the condensingof the refrigerant vapour; and

passing the liquid absorbent to the mixer unit whereby the liquidabsorbent contacts the gaseous mixture such that the gas is absorbedinto the liquid absorbent forming a solution of the liquid absorbent andthe gas.

In a further aspect there is provided a condenser for separating a gasfrom a refrigerant vapour in a gaseous mixture, the condensercomprising:

a housing for receiving the gaseous mixture and condensing therefrigerant vapour into liquid refrigerant; and

a mixer unit arranged within the housing for receiving a liquidabsorbent for absorbing the gas to form a solution of the gas and theliquid absorbent, the mixer unit being adapted for facilitating contactof the gaseous mixture with the liquid absorbent.

In still another aspect of the present invention there is provided amixer unit for mixing a gas with a liquid absorbent for absorbing thegas from a gaseous mixture of the gas and a refrigerant vapour toseparate the gas and the refrigerant vapour, the mixer unit comprising:

a mixer body for receiving the liquid absorbent and facilitating contactof gaseous mixture with the liquid absorbent for absorption of the gas,the mixer body being adapted for facilitating contact of the gaseousmixture with the liquid absorbent.

Condensing water from ambient air provides a way of supplementing freshor stored water supplies in remote or extreme locations where freshwater is scarce or otherwise unavailable, and may reduce reliance on, orthe need for, water to be transported to such locations. Similarly,where it is necessary to carry water supplies such as on a ship or boatduring a voyage, condensing water from ambient air provides analternative source of water during travel and so allows less reliance tobe placed on stored water. Indeed, by being able to condense water fromthe ambient air, stores of carried water may be reduced. In addition,condensing water from air provides some certainty as to the quality ofthe water and so provide a source of water in areas where there is doubtas to the quality of the existing water supplies or the available wateris known to be polluted or contaminated, or is otherwise not suitablefor the intended purpose of the water. Accordingly, one or moreembodiments of the present invention find application in a number ofpractical situations.

Moreover, as the ambient air is cooled and heat is generated when therefrigerant vapour is condensed during the operation of apparatusdescribed herein, the cooled ambient air and generated heat may be usedfor general cooling and heating purposes, respectively.

Accordingly, in a yet further aspect of the present invention there is amethod for providing heating from an apparatus during operation of theapparatus, the method comprising:

passing a gas into an enclosed space containing a gaseous mixture of thegas and refrigerant vapour evaporated from a liquid refrigerant, suchthat further refrigerant vapour evaporates into the enclosed space fromthe liquid refrigerant;

passing the gaseous mixture from the enclosed space to a condenser forcondensing the refrigerant vapour in the gaseous mixture back intoliquid refrigerant;

returning the gas from the gaseous mixture to the enclosed space;

recirculating the liquid refrigerant condensed from the gaseous mixturefor evaporation into the enclosed space; and

drawing off heat from the condenser to provide the heat.

In still another aspect of the present invention there is a method forproviding cooling from an apparatus during operation of the apparatus,the method comprising:

providing at least one cooling surface for contact with ambient air;

passing a gas into an enclosed space containing a gaseous mixture of thegas and refrigerant vapour evaporated from a liquid refrigerant, suchthat further refrigerant vapour evaporates into the enclosed space fromthe liquid refrigerant, and heat is thereby drawn into the liquidrefrigerant from the cooling surface cooling the cooling surface;

passing the gaseous mixture from the enclosed space;

contacting the cooled cooling surface with the ambient air to effectcooling of the ambient air; and

using the cooled ambient air to provide the cooling.

Apparatus for providing the heating and/or cooling are also specificallyencompassed by the present invention. It will be understood that it isnot necessary that the condensation/ cooling surface(s) of apparatusprovided for general heating and cooling purposes be cooled to, orbelow, the dew point of the ambient air. That is, the heating or coolingcan be achieved without collection of water from the ambient air.

Throughout this specification the word “comprise” or variations such as“comprises” or “comprising” will be understood to imply the inclusion ofa stated element, integer or step, or group of elements, integers orsteps, but not the exclusion of any other element, integer, or step, orgroup of elements, integers or steps.

The features and advantages of the present invention will become furtherapparent from the following description of the preferred embodiments ofthe present invention together with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of apparatus embodied by the present invention forcondensing water from ambient air;

FIG. 2 is a side view of the apparatus of FIG. 1;

FIG. 3 is a schematic view illustrating the operation of the apparatusof FIG. 1;

FIG. 4 is a rear view of the evaporator of the apparatus of FIG. 1;

FIG. 5 is a partial longitudinal cross-sectional view of the condenserof the apparatus of FIG. 1;

FIG. 6 is a cross-sectional view taken through B-B of the condenser ofFIG. 5;

FIG. 7 is a schematic view of a control system of the apparatus of FIG.1;

FIG. 8 is a schematic view illustrating the operation of a furtherapparatus embodied by the present invention for condensing water fromambient air; and

FIGS. 9 to 11 are flow diagrams illustrating the control system of theapparatus illustrated in FIG. 8.

FIG. 12 is a schematic end view of a solar heat tracking apparatus forproviding heating.

FIG. 13 is a schematic view showing heating being effected by thereflector of the apparatus of FIG. 12.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The apparatus 2 of FIG. 1 comprises an evaporator 4 containingiso-butane (R600a) refrigerant for cooling the evaporator to or belowthe dew point of water in ambient air flowing through the evaporator inuse. Briefly, the cooling of the evaporator is achieved by passing a gassuch as ammonia that is substantially inert with respect to therefrigerant into a headspace of the evaporator. This lowers the partialpressure of refrigerant vapour in the headspace and thereby causesfurther refrigerant to evaporate from the liquid refrigerant into theheadspace. The resulting gaseous mixture in the headspace comprising thegas and the refrigerant vapour; passes from the evaporator and the gasand the refrigerant vapour are separated. The separated refrigerantvapour is condensed, and the gas and condensed liquid refrigerant arerecirculated back to the evaporator 4 in a continuous cycle.

As shown more clearly in FIG. 2, the gaseous mixture from the evaporator4 passes to a condenser 6 due to a pressure differential between theevaporator and the condenser. The separation of the gas from therefrigerant vapour occurs in the condenser and is achieved by contactingthe gas within the gaseous mixture with a liquid absorbent fed into thecondenser. The gas is absorbed by the liquid absorbent to form asolution which passes from the condenser to a separation reservoir forseparation of the gas from the solution prior to the return of the gasto the evaporator. The liquid absorbent separated from the solution isrecirculated by a pump system generally indicated by the numerals 8 and10 to the condenser for further separation of gas from the gaseousmixture entering the condenser from the evaporator.

As shown schematically in FIG. 3, the evaporator 4 comprises a housing12 having a lower chamber 14 which is in fluid communication with aheadspace 16 of the evaporator through a plurality of spaced apart rowsof tubular pipes 18. The evaporator 4 is filled with liquid iso-butanerefrigerant 28 except for the headspace 16 of the evaporator. Spaces 20between the pipes provide a pathway for ambient air to flow through theevaporator over cooling fins 22. The upper side 22 a and under side 22 bof each fin 22 provide condensation surfaces for the condensation ofwater from the ambient air. The evaporator and thereby the fins 22 arearranged at a 45° angle relative to horizontal such that the condensedwater runs off the fins and falls onto a sloping surface of a casing 24housing the evaporator and the condenser, which directs the water to anoutflow spigot 26 for collection as illustrated in FIG. 2.

The gas 30, in this instance ammonia gas, is bubbled through the liquidrefrigerant from an inlet in the form of a diffuser 32 arranged withinthe lower chamber 14 of the evaporator. The ammonia gas passes upthrough the pipes 18 into the headspace 16 of the evaporator where itmixes with refrigerant vapour that has evaporated from the underlyingliquid refrigerant. The entry of the ammonia gas into the headspacecauses the partial pressure of the refrigerant vapour to decrease. Thiscauses further refrigerant to evaporate from the liquid refrigerant inthe evaporator. As a result, heat is drawn into the liquid refrigerantfrom the cooling the fins 22 which in turn cools ambient air flowingover the fins.

An outlet 34 is provided in the headspace 16 of the evaporator throughwhich the gaseous mixture flows to the condenser 6 through a feed pipe36. The feed pipe 36 opens into an upper region 38 of the condenserthrough an inlet 40. The condenser 6 is partly filled with a bath in abottom region 43 of the condenser, comprising a layer of liquidrefrigerant 28 overlaying a layer of a solution 42 of water anddissolved ammonia gas. A mixer unit 44 is suspended within the upperregion of the condenser by dual axis gimbals 46 secured to the walls ofthe condenser. The gimbals ensure that the mixer unit remains in asubstantially upright position if the ground surface on which theapparatus 2 is located is not horizontal.

A well 48 defined in an upper end of the mixer unit receives the liquidabsorbent 50 from a further inlet 52 provided in the upper region 38 ofthe condenser. The liquid absorbent comprises water containing asubstantially lower concentration of dissolved ammonia gas than thesolution 42 in the bottom region of the condenser. The liquid absorbent50 overflows from the rim 54 of the well and down the outer peripheralsurface 56 of the mixer unit prior to falling into the layer of liquidrefrigerant 28 of the bath.

As the liquid absorbent travels down the outer peripheral surface of themixer unit under the effect of gravity, it contacts the gaseous mixtureentering the condenser from the evaporator and absorbs ammonia from thegaseous mixture. As shown in FIG. 5, the mixer unit is provided with aplurality of spaced apart circumferential ridges 58 which form annularrings around the mixer unit. The rings produce turbulence in the flow ofthe liquid absorbent down the mixer unit as the absorbent passes overeach one. The turbulence facilitates mixing of the liquid absorbent withthe ammonia gas in the gaseous mixture from the evaporator and thereby,absorption of the ammonia gas into the liquid absorbent. Across-sectional view taken through B-B of the mixer unit is shown inFIG. 6. As can be seen, the liquid absorbent falls into the centre ofthe well 48 through aperture 60 of the inlet 52.

Returning to FIG. 3, the liquid absorbent and dissolved ammonia gas hasa higher density than the liquid refrigerant, and so settles from thelayer of the liquid refrigerant into the solution 42 in the bottomregion 43 of the condenser.

The solution 42 flows from the condenser through a feed pipe 62 andenters the separation reservoir 64 through an inlet 66. The storagereservoir 64 is partially filled with a solution of the liquid absorbentand dissolved ammonia gas, and has an internal headspace 68 filled withvapour from the solution and more particularly, ammonia gas and watervapour. In use, the separation reservoir is heated forcing the majorityof the ammonia gas in the solution entering from the condenser toevaporate into the internal headspace 68 of the separation reservoir.

An outlet 70 is provided in the separation reservoir through which theweaker solution 41 flows to a heating reservoir 72 of the pump systemthrough a feed pipe 74. The heating reservoir 72 is heated to asufficient temperature, typically the boiling point of the weakersolution, to force the weaker solution up through riser tube 76 intocollection reservoir 78. As the heated solution “percolates” up theriser tube 76 water vapour and ammonia gas evaporate from the solution,forming pockets of gas which are driven up through the riser tube withpassage of the solution to the collection reservoir 78. The solutionentering the collection reservoir therefore has a lower concentration ofdissolved ammonia gas compared to both the solution 42 entering theseparation reservoir and the solution passing from the storage reservoirto the heating reservoir.

After entering the collection reservoir 78, the solution is recirculatedto the condenser 6 as the liquid absorbent 50 for absorbing furtherammonia gas from the gaseous mixture passing into the condenser 6 fromthe headspace 16 of the evaporator 4 through feed pipe 36.

More particularly, as indicated in FIG. 3, the liquid absorbent 50exiting the riser tube 76 pools within the collection reservoir 78 andtravels back down recycling tube 80 which passes through the solution 42in the separation reservoir 64 in a heat exchange relationship with theinlet 66, for heat exchange with the solution entering the separationreservoir from the condenser. From the storage reservoir, the recyclingtube 80 directs the liquid absorbent to inlet 52 of the condenser.

A feed pipe 82 feeds the ammonia gas and water vapour entering thecollection reservoir from riser tube 76 to a common feed pipe 84 whichopens at one end into the headspace 68 of the separation reservoirthrough outlet 86. An opposite end of the common feed pipe 84 opens intothe diffuser 32 arranged in the evaporator 4 for return of the ammoniagas to the headspace 16 of the evaporator. The common feed pipe 84 hasan inclined section 88 for trapping water which condenses in the commonfeed pipe from water vapour entering with ammonia gas from thecollection reservoir 78 and separation reservoir 64, and directing thecondensed water back to the storage reservoir.

As also indicated in FIG. 3, the common feed pipe 84 passes through aheat exchanger 90 comprising a section of the feed pipe 36 transportingthe gaseous mixture from the headspace 16 of the evaporator 4 to thecondenser 6. A further feed pipe 92 recycling condensed refrigerant 28from the condenser to the lower chamber 14 of the evaporator 4 alsopasses through the heat exchanger 90 and continues on in a heat exchangerelationship with the common feed pipe 84 from the heat exchanger 90 tothe lower chamber 14 of the evaporator 4. As will be appreciated, theheat exchanger 90 facilitates heat exchange between the gaseous mixturein the heat exchanger and the refrigerant in feed pipe 92 and theammonia gas in the common feed pipe 94. Similarly, the side by sidearrangement of the common feed pipe 84 and feed pipe 92 from the heatexchanger 90 to the evaporator 4 allows for heat exchange between therefrigerant in feed pipe 92 and the ammonia gas in the common feed pipe.

As described above, the evaporator 4 and condenser 6 are housed within acasing 24. As best illustrated in FIG. 7, the casing 24 has a main airintake 96 and a fan 98 arranged at an outlet 100 for drawing ambient airinto the casing from the atmosphere through the main air intake. Theambient air flows through the evaporator into contact with the coolingfins 22 causing water to condense from the air onto the fins 22, andthen into contact with the housing 94 of condenser 6. As the cooled airpasses over the housing of the condenser, heat is drawn off from thehousing. The refrigerant vapour in the upper region of the condenser andthe underlying liquid refrigerant are thereby also cooled.

For efficient operation, the flow rate of the ambient air through thecasing 24 is adjusted to optimise condensation of water per unit volumeof the ambient air flowing through the evaporator, while maintainingsufficient air flow over the condenser for heat transfer from thecondenser to the ambient air for condensation of the refrigerant vapourwithin the condenser. As will be understood, the apparatus is operatedsuch that the cooling fins are sufficiently cooled without freezing thecondensed water.

For any given prevailing atmospheric conditions, there is a specifichumidity value measured in grams of water vapour per kilogram of theair. For example, a specific humidity of between 4.5 and 6 grams ofmoisture per kilogram of air correlates to a dry bulb temperature ofbetween 1° C. and 6.5° C. In use, the apparatus is operated at such thatthe specific humidity of the ambient air flowing from the condensationsurfaces of the cooling fins 22 is reduced to a specific humiditycorrelating with a specific selected dry bulb temperature or temperaturerange.

More particularly, the fan 98 is initially operated at maximum speed toachieve maximum air flow through the casing 24 and the dew point of theambient air entering the evaporator is determined by a sensor 102. Thesensor is arranged so as to be progressively cooled by the ambient airas the ambient air entering the evaporator is cooled by the cooling fins22. When condensation forms on the sensor 102 from the ambient air, thesensor is short circuited indicating the dew point of the ambient air.This temperature is compared in control module 106 to the dry bulbtemperature of the air leaving the evaporator measured by a temperaturesensor 104. If the temperature measured by temperature sensor 104 isabove the dew point of the water in the ambient air determined by sensor102, the speed of the fan is progressively reduced on command from thecontrol module 106 lowering the flow rate of the ambient air through theevaporator. This continues until the temperature of the ambient air islowered to the dew point of the water in the ambient air to achievecondensation of the water onto the cooling fins 22.

Once the optimum flow rate of the ambient air over the evaporator 4 hasbeen achieved, the temperature of the condensed refrigerant 28 in thecondenser 6 is measured by a further temperature sensor 112 and comparedin the control module 106 with the total pressure in the upper region 38of the condenser measured by pressure sensor 114. As the pressure in theupper region of the condenser varies according to ambient conditions,there are temperature and pressure conditions within the condenser foroptimum condensation of the refrigerant vapour.

The temperature and pressure measured by the temperature sensor 112 andpressure sensor 114 are compared in control module 106 and the controlmodule determines whether the optimum conditions for condensation of therefrigerant vapour have been achieved. If the control module determinesthat the temperature in the condenser is too high for the condensationof the refrigerant vapour, the speed of the fan 98 is progressivelyincreased on command from the control module. This increases the flowrate of the cooled ambient air passing from the evaporator to thecondenser, causing further heat to be removed from the housing of thecondenser by the ambient air and the temperature in the condenser tothereby be progressively lowered. The speed of the fan continues to beincreased until a temperature in the condenser' at which condensation ofthe refrigerant vapour occurs has been reached.

After a short time delay of typically 1 to 2 minutes, the dew point ofthe ambient air entering the evaporator and the dry bulb temperature ofthe ambient air leaving the evaporator are again measured by temperaturesensors 102 and 104, and those temperatures are compared in the controlmodule. If a temperature measured by the temperature sensor 104 hasrisen above the dew point of the water, an air-intake in the form of ahinged by-pass damper 108 arranged in a lower region of the casing 24 isopened to at least a limited extent by an actuator 110 operated by thecontrol module. The opening of the by-pass damper 108 allows uncooledambient air indicated by the arrow, to flow into the casing through thefurther air-intake into contact with the condenser. This reduces theflow rate of the ambient air through the evaporator to that required forcooling of the ambient air to the dew point of the water in the ambientair, while maintaining or increasing the flow rate of the ambient airpast the condenser.

The control module 106 continues to monitor the temperatures of the airflow of the ambient air through the casing measured by temperaturesensors 102 and 104, as well as the temperature of the liquidrefrigerant in the condenser and the total pressure in the upper regionof the condenser measured by pressure sensor 114 and temperature sensor112, and to adjust the position of the damper 108 and the speed of thefan 98 in response to changing ambient conditions as required forcontinued condensation of water from the ambient air onto the coolingfins 22 and condensing of the refrigerant vapour within the condenser 6.The monitoring cycle is repeated at regular intervals to ensure optimumefficiency of the apparatus and thereby, maximum production of waterfrom the ambient air. The timing circuit for initiating operation of themonitoring cycle is also located within the control module. Such controlcircuitry is well within the scope of the skilled addressee.

A further apparatus for collecting water from ambient air embodied bythe present invention is illustrated schematically in FIG. 8. Thisapparatus differs from that illustrated in FIG. 3 in that the pumpsystem comprising the heating reservoir 72 and the collection reservoir78 is located before the separation reservoir 64. More particularly, thesolution 42 from the condenser 6 flows directly into the heatingreservoir 72 where it is heated for separation of dissolved ammonia gasfrom the liquid absorbent. As described above, as the heated solution 42“percolates” up the riser tube 76, water vapour and ammonia gasevaporate from the solution, forming pockets of the gas which are drivenup through the riser tube into the collection reservoir. As with theembodiment illustrated in FIG. 3, the liquid absorbent 50 which collectsin the collection reservoir is channelled back into the condenser 6through recycling tube 80 for contact with further gaseous mixturepassing from the evaporator 4. However, rather than the separated gasbeing channelled to diffuser 32 in the evaporator as in the embodimentshown in FIG. 3, the separated ammonia gas passes through feed pipe 82into the upper region 38 of the condenser. This minimises the passage ofwater vapour evaporated from the liquid absorbent passing into theevaporator.

The solution of the liquid absorbent and remaining dissolved ammonia gasthat passes from the heating reservoir 72 to the separation reservoir isheated in separation reservoir 64 as above, to effect evaporation of theammonia gas for return of the gas to the diffuser 32 in the evaporatorthrough feed pipe 84.

As further shown in FIG. 8, this apparatus also incorporates a waterreturn system 116 for returning water which accumulates in theevaporator 4 to the condenser 6. The water return system comprises afloat valve incorporating a ball float 118 arranged in a storagecylinder 120 which opens into the evaporator through feed conduit 122.The ball float 118 normally rests on the open end 124 of the drainconduit 126, thereby closing the drain conduit. A pressure equalisingconduit (not shown) connects the upper region of the storage cylinderabove the ball float 118 to a lower region of the storage cylinder belowthe ball float. The density of water is greater than that of therefrigerant and so settles to the bottom of the storage cylinder. Theball float has a density such that it will not float in the refrigerantbut will float in the water. When sufficient water accumulates in thebottom of the storage cylinder 120, the ball float is lifted from thedrain conduit 126, allowing water to flow into the drain conduit towater return heating reservoir 128, until the level of the water in thestorage cylinder decreases such that the ball float returns to itsnormal position sealing the open end 124 of the drain conduit preventingthe escape of liquid refrigerant from the evaporator.

In use, the water return heating reservoir 128 is heated by an electricelement in use forcing the water to percolate up water return pipe 130which empties into the condenser 6. As will be appreciated, the waterwhich collects in the storage cylinder 120 from the evaporator willcontain an amount of dissolved ammonia gas. It will also be understoodthat the apparatus shown in FIG. 3 may also be provided with a waterreturn system 116.

Flow diagrams illustrating operation of the control system of theapparatus of FIG. 8 are shown in FIG. 9 to FIG. 11. In this controlsystem, temperature sensor 102 has been omitted and the flow of ambientair into contact with the cooling fins 22 of the evaporator is varied tomaintain the temperature measured by temperature sensor 104 at atemperature in a range of from 4° C. to 5° C. At the commencement ofoperation of the apparatus, the solution in each of water reservoir 128,separation reservoir 64 and heating reservoir 72 is heated to from 90°C. to 95° C. by respective electric heating elements. The by-pass damper108 is in a closed position and the fan 98 is operated at maximum speed.The temperature measured by the temperature sensor 104 is then measuredat approximately 2 minute intervals and the speed of the fan is varied,or the by-pass damper 108 is opened, in 10% increments until thetemperature measured by the temperature sensor is within the range offrom 4° C. to 5° C. If with further monitoring, the temperature measuredfalls below 4° C. and the by-pass damper 108 is fully open, heating ofthe solution in separation reservoir 64 is reduced in 10% incrementscorresponding to decrease of about 9° C. each time. This reduces therate of evaporation of the ammonia gas from the solution in theseparation reservoir and thereby, the amount of ammonia gas returning tothe evaporator via the diffuser 32 of the evaporator 4 causing thetemperature of the cooling fins 22 to rise. Alternatively, the speed ofthe fan 98 can also be increased in order to raise the temperaturemeasured by the temperature sensor 104.

The temperature of the condensed liquid refrigerant and the pressurewithin the condenser 6 are separately monitored at approximately 2minute intervals by temperature sensor 112 and pressure sensor 114. Ifthe determined pressure and temperature are not at predetermined levelsfor effecting condensation of refrigerant vapour in the condenser, thespeed of the fan is increased in 10% increments or alternatively, theheating of the solution in the separation reservoir 64 is decreased in10% increments, until the temperature and pressure measured bytemperature sensor 112 and pressure sensor 114 are below thepredetermined levels. For the combination of ammonia gas and iso-butanerefrigerant as utilised in the embodiments shown in FIGS. 3 and 8, thepressure within the condenser will generally be maintained below 432 kPawhile the temperature of the condensed liquid refrigerant will generallybe maintained below 40.6° C. However, it will be appreciated thatdifferent temperature and pressure settings will be required when systemgas and refrigerant other than ammonia gas and iso-butane refrigerantare utilised.

The power for driving the operation of the electrical components of theapparatus embodied by the invention such as the fan 98 is preferablyprovided by mains electricity. However, instead, or as well, apparatusmay be provided with a solar panel comprising arrays of photovoltaiccells for providing sufficient electricity to meet the entire energyrequirements of the apparatus, including all heating requirements anddriving the fan 98 and control module 106. In this instance, theapparatus will typically also be provided with one or more rechargeablebatteries and a recharging circuit for recharging the battery orbatteries using electrical energy generated by the solar panel. Suchrecharging systems are well known in the art.

Alternatively, a solar heating apparatus 132 with a tracking mechanismfor tracking solar heat such as the type illustrated in FIG. 12 and FIG.13 may be utilised to provide heating for a water condenser apparatusembodied by the invention. The tracking mechanism comprises a balance133 on which a parabolic reflector 136 is mounted. The balanceincorporates a frame pivotally mounted on a stand 138. The frameconsists of hollow side tanks 140 approximately half filled with aliquid refrigerant such as freon, and opposite end members 142. Theinteriors of the tanks are connected together through the passageway ofa hollow feed tube 144. A shade panel 146 lies along each side tank forshading the corresponding tank from behind. A reflective surface on afront side of each shade panel reflects heat onto the corresponding tankwhen the tank is facing the sun.

The side tanks 140 are arranged such that in use, a first of the tanksis exposed to the sun to a greater degree than the second of the tanks.As the first tank is heated by the sun, the pressure in the tankincreases creating a pressure differential between the tanks, and freonprogressively flows from the first tank to the other through feed tube144. As the freon flows into the second tank, the weight of the secondtank becomes heavier than the first, causing the frame of the balance topivot about a pivot pin 134 and the reflector to be moved in a westerndirection substantially synchronously with the movement of the sun.

As shown more dearly in FIG. 13, a flexible drive shaft 150 is rotatedabout its longitudinal axis with rotation of the frame about the pivotpin. More specifically, the drive shaft 150 is secured at one end aboutthe pivot pin 134, and carries reflector 136 on an opposite end. Theopposite end of the drive shaft 150 is arranged so as to besubstantially concentric with the longitudinal axis of the component ofthe water condenser apparatus to be heated. The reflector 136 is therebyrotated about the component to be heated with rotation of the driveshaft 150.

The rear reflective surface 148 of the reflector 136 is inclinedrelative to the axis of rotation of the drive shaft. As the rearreflective surface is inclined, the focal length of the reflector variesfrom the top of the reflector to the bottom of the reflector. Thisenables the reflector to focus sunlight impinging on the reflector ontothe component to be heated when the sun is in different positionsthroughout the day. The component to be heated may for instance comprisethe separation reservoir 64, heating reservoir 72 or water returnheating reservoir 128. Alternatively, a combination of one or more ofthese may be heated. In this latter instance, the reservoirs may bearranged adjacent to each other for being heated by an appropriatelydimensioned reflector 136.

At the end of the daylight period, when the heat of the sun decreases,the pressure differential between the side tanks 140 reduces and thedirection of the flow of the freon through the hollow tube 144connecting the tanks reverses. The return of the freon to the first tankcauses the weight of that tank to increase and the frame of the balanceto progressively pivot about the stand in an opposite direction, and thereflector to thereby be progressively returned to its initial sunriseposition. A conventional suitable shock absorber 154 connected at one tothe frame and at an opposite end to the stand, is provided forinhibiting buffeting of the reflector by wind.

Typically, the parabolic reflector 136 is dimensioned for providingheating in excess of the amount required. The excess heat may be drawnoff and stored in heat banks for use when sunlight is reduced by cloudsor during other periods of low sunlight availability such as at sunsetStoring the excess heat in the heat banks for subsequent use may alsoallow a night cycle of the water condenser apparatus to operate toachieve further condensation of water from ambient night air.

As heat is generated by the apparatus of FIG. 3 and FIG. 8, rather thanexhausting the warmed air that passes from the condenser 6 into theatmosphere, the warmed air may be used for general heating purposes. Forinstance, the warmed air may be drawn into ducting by another fan, whichdirects the warmed air into a room or other space through a vent.Similarly, cooled air passing from the cooling fins 22 of the evaporator4 may be used for general cooling purposes. For instance, the cooled airmay be drawn into ducting by a fan as above. The cooled air can then bedirected into further ducting by a sail type valve which exhausts thecooled air onto the condenser and/or other ducting opening into a roomor space through a vent which may be the same or different to a ventthrough which warm air is exhausted. Cooling of the condenser can becompensated by increasing the speed of the fan 98 or by opening theby-pass damper 108 to increase the flow of ambient air flowing intocontact with the condenser.

Moreover, besides collecting water from ambient air for drinking orother purposes, apparatus embodied by the invention may be used as adehumidifier for dehumidifying silos or other interior spaces where itis desirable to minimise the water content of the air. Similarly, theapparatus may be used for removing water from locations such as from theinterior of pipes used for channelling hydrophobic fluids such as oil orpetroleum. In such applications, air may be drawn from the silo orpipe(s) prior to being returned to the silo or pipe(s) following theextraction of the water by the apparatus. When a silo (eg wheat silo) isto be dehumidified, the air may first be filtered to remove dust fromthe air prior to the air contacting the cooling fins of the apparatus.

Although the present invention has been described hereinbefore withreference to a number of preferred embodiments, the skilled addresseewill appreciate that numerous changes and modifications are possiblewithout departing from the spirit or scope of the invention. The presentembodiments described are, therefore, to be considered in all respectsas illustrative and not restrictive.

For instance, rather than a by-pass damper 108, the apparatus of theinvention may be provided with an adjustable valve for modulating theflow rate of the ambient air past the condenser 6. In addition, a gasand a liquid refrigerant other than ammonia gas and iso-butane may beutilised. For example, other combinations of gases and liquidrefrigerants that may be used include ammonia gas and propane, hydrogenchloride gas and propylene, ammonia gas and pentane, hydrogen chloridegas and iso-butane, and methylamine gas and iso-butane.

Moreover, instead of using solar energy or mains electricity to provideheating, heat from an external waste heat source such as a boiler,engine hot water, or the discharge heat from a refrigeration orair-conditioning condenser may be channelled to components requiringheating such as the separation reservoir 64 by conduit(s), and heatingachieved by heat transfer contact with the conduit(s). Similarly,embodiments of the invention may be provided without a fan for drawingthe ambient air through the evaporator and/or past the condenser. Inthis instance, flow of the ambient air through the casing may beachieved by thermal convection currents as a result of temperaturedifferences between the evaporator and external ambient airtemperatures.

1. A method for collecting water from ambient air, the methodcomprising: providing at least one condensation surface for contact withthe ambient air; passing a gas into an enclosed space containing agaseous mixture of the gas and refrigerant vapour evaporated from aliquid refrigerant such that further refrigerant vapour evaporates intothe enclosed space from the liquid refrigerant, and heat is therebydrawn into the refrigerant from the condensation surface cooling thecondensation surface to, or below, the dew point of the water in theambient air; passing the gaseous mixture from the enclosed space;contacting the cooled condensation surface with the ambient air toeffect condensation of water from the ambient air onto the condensationsurface; and collecting the condensed water.
 2. A method according toclaim 1 further comprising condensing the refrigerant vapour in thegaseous mixture passed from the enclosed space back into liquidrefrigerant to separate the refrigerant vapour from the gas, returningthe gas from the gaseous mixture to the enclosed space for generatingmore of the gaseous mixture, and recirculating the liquid refrigerantcondensed from the gaseous mixture.
 3. A method according to claim 2wherein the gaseous mixture is passed from the enclosed space intocontact with a liquid absorbent that absorbs the gas from the gaseousmixture thereby forming a solution, and the gas is separated from thesolution for the return of the gas to the enclosed space and recyclingof the liquid absorbent for contact with more of the gaseous mixture. 4.A method according to claim 2 wherein the liquid refrigerant condensedfrom the gaseous mixture is recirculated concurrently with the passageof the gas into the enclosed space and passage of the gaseous mixturefrom the enclosed space into contact with the liquid absorbent, suchthat the condensation surface is cooled in a continuous cycle. 5.(canceled)
 6. A method according to claim 1 wherein the gas is bubbledthrough the liquid refrigerant into the enclosed space.
 7. A methodaccording to claim 1 further comprising monitoring temperature ofambient air flowing from the condensation surface, and adjusting theflow rate at which the ambient air flows into contact with thecondensation surface to a desired flow rate to promote the condensationof the water from the ambient air onto the condensation surface.
 8. Amethod according to claim 2 wherein the ambient air is cooled by contactwith the condensation surface and the cooled ambient air is used forcooling the refrigerant vapour in the gaseous mixture passed from theenclosed space, to facilitate condensing the refrigerant vapour backinto the liquid refrigerant.
 9. A method according to claim 8 whereinthe refrigerant vapour is condensed in a condenser and the methodfurther comprises adjusting flow rate of the ambient air flowing fromthe condensation surface to promote the condensation of the refrigerantvapour.
 10. A method according to claim 9 wherein the flow rate of theambient air flowing from the condensation surface is adjusted relativeto a flow rate of the ambient air flowing into contact with thecondensation surface.
 11. A method according to claim 9 comprisingmonitoring the flow rate of the ambient air flowing from thecondensation surface to evaluate whether it needs to be adjusted topromote the condensation of the refrigerant vapour in the condenser, themonitoring comprising: measuring pressure within the condenser;measuring temperature within the condenser; and assessing the measuredpressure and the measured temperature.
 12. (canceled)
 13. (canceled) 14.An apparatus for collecting water from ambient air, the apparatuscomprising: at least one condensation surface for contact with theambient air; an evaporator for receiving liquid refrigerant and definingan enclosed space for a gaseous mixture of refrigerant vapour evaporatedfrom the liquid refrigerant and a gas; an inlet opening into theevaporator for passage of the gas into the space to cause furtherevaporation of the liquid refrigerant into the space such that heat isdrawn into the liquid refrigerant from the condensation surface, and thecondensation surface is thereby cooled to, or below, the dew point ofthe water in the ambient air to effect condensation of water from theambient air onto the condensation surface for collection of the water;and an outlet for passage of the gaseous mixture from the space.
 15. Anapparatus according to claim 14 further comprising a separation systemfor separating the gas in the gaseous mixture from the refrigerant andcondensing the refrigerant vapour back into liquid refrigerant, forreturn of the gas to the enclosed space in the evaporator and recyclingof the liquid refrigerant to the evaporator.
 16. An apparatus accordingto claim 15 wherein the separation system comprises a condenser forreceiving the gaseous mixture from the evaporator and condensing therefrigerant vapour in the gaseous mixture back into liquid refrigerant,the condenser being adapted to receive liquid absorbent and facilitatecontact of the gaseous mixture with the liquid absorbent for adsorptionof the gas into the liquid absorbent to form a solution and therebyseparate the gas from the refrigerant vapour.
 17. An apparatus accordingto claim 16 wherein in use, the condenser houses a bath comprising alayer of the liquid refrigerant and a layer of the solution, and thecondenser is adapted for receiving the gaseous mixture for contact ofthe gaseous mixture with the liquid absorbent to form the solution,prior to passage of the solution into the bath.
 18. An apparatusaccording to claim 17 wherein the liquid refrigerant has a lower densitythan the solution, and the solution separates from the layer of liquidrefrigerant into the layer of the solution.
 19. An apparatus accordingto claim 16 further comprising a mixer unit arranged within thecondenser for receiving the liquid absorbent, wherein the mixer unit isadapted for creating a flow of the liquid absorbent over a surface ofthe mixer unit for facilitating the contact of the gas with the liquidabsorbent.
 20. An apparatus according to claim 19 wherein the mixer unithas an open well for receiving the liquid absorbent and providing theflow of the liquid absorbent down the surface of the mixer unit withoverflow of the liquid absorbent from the well.
 21. (canceled) 22.(canceled)
 23. An apparatus according to claim 16 wherein the separationsystem further includes a separation reservoir for evaporation of thegas from the liquid absorbent, the separation reservoir comprising: ahousing; an inlet for passage of the liquid absorbent into the housing,the gas evaporating from the liquid absorbent within the housing; and anoutlet for return of the gas evaporated from the liquid absorbent to theevaporator.
 24. An apparatus according to claim 23 wherein theseparation reservoir is adapted for being heated to facilitateevaporation of the gas from liquid absorbent.
 25. An apparatus accordingto claim 16 further comprising a pump system for elevating the liquidabsorbent to an elevated position for flow of the liquid absorbent tothe condenser for contact with further of the gaseous mixture from theevaporator, the pump system comprising: a heating reservoir forreceiving the liquid absorbent and being heated for causing the liquidabsorbent to be forced from the heating reservoir; a riser tube forreceiving the liquid absorbent from the heating reservoir upon theheating reservoir being heated; and a collection reservoir arranged atthe elevated position and into which the tube opens for collection ofthe liquid absorbent, the collection reservoir being adapted for passageof the liquid absorbent from the collection reservoir to the condenser.26. An apparatus according to claim 25 wherein the collection reservoirhas a first outlet for passage of the liquid absorbent from thecollection reservoir to the condenser, an interior space for receivingthe gas together with absorbent vapour which evaporate from the liquidabsorbent with travel along the riser tube, and a further outlet forpassage of the gas separated from the liquid absorbent from thecollection reservoir to the evaporator.
 27. An apparatus according toclaim 14 further comprising a control system for controlling flow rateof the ambient air into contact with the condensation surface, thecontrol system comprising: a temperature sensor for determiningtemperature of the ambient air flowing from the condensation surface,the control system being adapted to monitor the temperature determinedby the temperature sensor and adjust flow rate of the ambient airflowing into contact with the condensation surface to promotecondensation of the water from the ambient air onto the condensationsurface.
 28. An apparatus according to claim 27 adapted to direct theambient air flowing from the condensation surface to the condenser, andwherein the control system further includes an adjustable air intakeoperable to adjust flow rate of the ambient air flowing from thecondensation surface to the condenser relative to a flow rate of theambient air flowing into contact with the condensation surface, tothereby alter temperature and pressure within the condenser to promotethe condensation of the refrigerant vapour.
 29. An apparatus accordingto claim 28 wherein the control system further includes a temperaturesensor for measuring temperature in the condenser, and a pressure sensorfor measuring pressure within the condenser, and the control system isfurther adapted to assess the temperature measured by the temperaturesensor and the pressure measured by the pressure sensor, and operate theadjustable air intake to alter the flow rate of the ambient air flowingto the condenser.
 30. (canceled)
 31. (canceled)
 32. An evaporator foreffecting condensation of water from ambient air, the evaporatorcomprising: at least one condensation surface for contact with theambient air; a housing for receiving liquid refrigerant and having anenclosed interior space for a gaseous mixture of refrigerant vapourevaporated from the liquid refrigerant and a gas; an inlet for passageof the gas into the space to cause further evaporation of the liquidrefrigerant into the enclosed space such that heat is drawn into theliquid refrigerant from the condensation surface and the condensationsurface is thereby cooled to, or below, the dew point of the water inthe ambient air to effect condensation of the water from the ambient aironto the condensation surface for collection of the water; and an outletfor passage of the gaseous mixture from the enclosed space.
 33. Anevaporator according to claim 32 wherein the, or each, condensationsurface is a surface of cooling fin respectively, and the housing of theevaporator comprises: an upper region for receiving the gaseous mixtureof the gas and the refrigerant vapour; a lower region for being at leastpartly filled with the liquid refrigerant and being spaced from theupper region; and at least one conduit that opens at one end into theupper region of the housing and at an opposite end into the lowerregion; and wherein the, or each, cooling fin is arranged between theupper region and the lower region for contact with the ambient air. 34.(canceled)
 35. A method for separating a gas from a refrigerant vapourin a gaseous mixture, the method comprising: providing a condenseradapted for condensing the refrigerant vapour into liquid refrigerant,the condenser housing a mixer unit for receiving a liquid absorbent forabsorbing the gas and which is adapted for facilitating contact of theliquid absorbent with the gaseous mixture; passing the gaseous mixtureinto the condenser to effect the condensing of the refrigerant vapour;and passing the liquid absorbent to the mixer unit whereby the liquidabsorbent contacts the gaseous mixture such that the gas is absorbedinto the liquid absorbent forming a solution of the liquid absorbent andthe gas.
 36. (canceled)
 37. (canceled)
 38. A condenser for separating agas from a refrigerant vapour in a gaseous mixture, the condensercomprising: a housing for receiving the gaseous mixture and condensingthe refrigerant vapour into liquid refrigerant; and a mixer unitarranged within the housing for receiving a liquid absorbent forabsorbing the gas to form a solution of the gas and the liquidabsorbent, the mixer unit being adapted for facilitating contact of thegaseous mixture with the liquid absorbent.
 39. A mixer unit for mixing agas with a liquid absorbent for absorbing the gas from a gaseous mixtureof the gas and a refrigerant vapour to separate the gas and therefrigerant vapour, the mixer unit comprising: a mixer body forreceiving the liquid absorbent and facilitating contact of gaseousmixture with the liquid absorbent for absorption of the gas, the mixerbody being adapted for facilitating contact of the gaseous mixture withthe liquid absorbent.
 40. A method for providing heating from anapparatus during operation of the apparatus, the method comprising:passing a gas into an enclosed space containing a gaseous mixture of thegas and refrigerant vapour evaporated from a liquid refrigerant, suchthat further passing the gaseous mixture from the enclosed space to acondenser for condensing the refrigerant vapour in the gaseous mixtureback into liquid refrigerant; passing the gaseous mixture from theenclosed space to a condenser for condensing the refrigerant vapour inthe gaseous mixture back into liquid refrigerant; returning the gas fromthe gaseous mixture to the enclosed space; recirculating the liquidrefrigerant condensed from the gaseous mixture for evaporation into theenclosed space; and drawing off heat from the condenser to provide theheat.
 41. (canceled)
 42. A method for providing cooling from anapparatus during operation of the apparatus, the method comprising:providing at least one cooling surface for contact with ambient air;passing a gas into an enclosed space containing a gaseous mixture of thegas and refrigerant vapour evaporated from a liquid refrigerant, suchthat further refrigerant vapour evaporates into the enclosed space fromthe liquid refrigerant, and heat is thereby drawn into the liquidrefrigerant from the cooling surface cooling the cooling surface;passing the gaseous mixture from the enclosed space; contacting thecooled cooling surface with the ambient air to effect cooling of theambient air; and using the cooled ambient air to provide the cooling.43. (canceled)
 44. (canceled)
 45. A solar heating device for providingsolar heating, the device comprising: at least one pair of spaced apartreservoirs for being differentially heated by solar heat from the sunand being pivotable about a pivot axis, one or both of the reservoirsbeing partly filled with a refrigerant; at least one conduit for passageof the refrigerant from the one reservoir to the other reservoir uponthe one reservoir being heated by the solar heat relative to the otherreservoir, and return of the refrigerant to the one reservoir upon theone reservoir cooling relative to the other reservoir, the pair ofreservoirs being pivoted about the pivot axis in one direction withpassage of the refrigerant from the one reservoir to the other reservoirand in an opposite direction with the return of the refrigerant to theone reservoir; and a reflector for reflecting the solar heat onto anobject to be heated, the reflector being arranged to rotate about anaxis of rotation in a first direction for substantially maintaining thereflection of the solar heat on the object with the pivoting of the pairof reservoirs about the pivot axis in the one direction, and beingrotatable about the axis of rotation in an opposite direction as thepair of reservoirs are pivoted in the opposite direction about the pivotaxis.